1. Field of the Invention
The present invention relates generally to tools adapted for applying the tensile force required to release the fifth wheel latch on a tractor and semi-trailer assembly. More specifically, the present invention comprises a release tool which alters the direction of the applied force from the horizontal to a substantially vertical orientation, whereby the person using the present tool can use his or her body weight to apply the release force, merely by stepping on a treadle provided with the tool.
2. Description of the Related Art
Large and/or heavy loads are conventionally carried over the road by truck tractor and semi-trailer units, in which the tractor provides the support for the forward end of the trailer. The trailer includes a hitch or “king” pin extending downwardly from its forward end, which engages a so-called “fifth wheel” disposed generally horizontally on the back of the truck tractor, behind the cab. The connection of the trailer to the tractor is essentially automatic, as the latch is spring loaded to a closed position and engages the king pin of the trailer when the tractor is backed into position for the fifth wheel plate and latch to engage the king pin of the trailer.
Release of the trailer from the tractor, however, requires specific action on the part of the trucker. The trucker must support the forward end of the trailer and manipulate a handle extending from the fifth wheel release, and apply sufficient tensile force to open the release in order to allow the tractor to be driven away from the trailer. Oftentimes, the king pin binds in the fifth wheel, due to the tractor and trailer being parked on slightly different lateral grades or slopes, or perhaps excessive dirt or other foreign matter contaminating the release mechanism, etc. At best, a considerable amount of force is required to overcome the spring tension which holds the release mechanism in its normally closed position. When other factors result in even greater release force being required, the necessary force can tax the strength of even the strongest trucker.
As a result, a number of fifth wheel release tools have been developed over the years. Many such tools are adapted to serve multiple purposes, e.g. serve as a fifth wheel release tool as well as a tool for pulling the locking pins securing the rearward tandem axles of the trailer, to provide for their positional adjustment. As a result, most such tools are not adapted to provide any real leverage or mechanical advantage for use as a fifth wheel release tool. Other fifth wheel release tools have been configured as levers, to provide additional mechanical advantage to the user. However, all of these tools of which the present inventors are aware, require arm and upper back exertion by the person using the tool.
The upper back exertion required in using conventional fifth wheel release tools can frequently result in some form of back injury to the trucker, e.g. a back sprain, pulled muscle, etc. Such injuries can be extremely painful at best, and may be completely incapacitating to the trucker. In fact, OSHA has found that the activity of releasing the fifth wheel of a tractor-trailer combination is among the top three causes of injuries to truckers.
Accordingly, a need will be seen for a fifth wheel release tool which does not require any significant upper back strength or exertion on the part of a user of the tool. The present fifth wheel release tool in its various embodiments serves to change the direction of the applied tensile force on the fifth wheel release handle from essentially horizontal, to an essentially vertical orientation. The present release tool includes a treadle or stirrup which is positioned near but somewhat above the underlying surface, into which the trucker may place his or her foot. The trucker need only stand in the stirrup to apply all of his or her weight to the release, thereby quickly and easily releasing all but the most stubborn fifth wheel releases. The present release tool enables the user to apply considerably more force than is available with conventional tools, particularly those tools which do not provide any mechanical advantage for the arm and upper back strength of the user.
A discussion of the related art of which the present inventors are aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 4,251,089 issued on Feb. 17, 1981 to Michael G. Skaggs, titled “Tractor-Trailer Vehicle Decoupling Tool,” describes a fifth wheel hitch release tool comprising a lever bar with a latch release engaging rod extending therefrom. The lever bar has a handle end and an opposite fulcrum end, with the latch release rod connected closer to the fulcrum end of the lever bar. The tool is used by hooking the engaging rod on the fifth wheel release handle, and placing the fulcrum end of the lever bar against the side of an outer tire. The longer handle end is then pulled outwardly to provide a mechanical advantage in the application of force to the release handle. While this tool may facilitate the release of a sticky or stubborn fifth wheel latch, it does so using only the upper body strength of the user. No transfer of force from the horizontal to the vertical or utilization of the user's weight is provided by the Skaggs tool.
U.S. Pat. No. 5,201,559 issued on Apr. 13, 1993 to Russell W. Boring et al., titled “King Pin Release Tool,” describes a tool which uses the slide hammer principle. The Boring et al. tool has two concentric, telescoping shafts, with the shafts initially retracted upon connection to the fifth wheel latch release handle. The second shaft is then sharply extended, with its mass providing a sudden force to the first shaft connected to the release handle, to jerk the release handle and latch open. This tool requires significant upper body strength for operation, and does not provide any means of transferring the required force to the vertical to allow the trucker to merely step on the distal end of the tool to apply the required force.
U.S. Pat. No. 5,344,201 issued on Sep. 6, 1994 to A. Dean Offin, titled “Multi-Function Tool For Truck Operators,” describes a tool comprising a bar with a release handle engaging hook on the distal end, and a handle extending at a right angle from the opposite end of the bar. The tool is used by applying a release force straight out from the hitch release handle, which requires significant upper back exertion from the trucker using the tool. The injury potential when using such a tool has been noted further above. In contrast, the present tool transfers the force required from a substantially horizontal direction to a substantially vertical direction, allowing the trucker to use his or her body weight to apply the force required for hitch release.
U.S. Pat. No. 5,378,007 issued on Jan. 3, 1995 to Ronald W. Joyce, titled “Trailer Hitch Uncoupling Apparatus And Method Of Use,” describes a combination tool for use in releasing a fifth wheel hitch, as well as in releasing the slider locking pins for adjusting the position of the rear wheels on a semi-trailer. When used to release the fifth wheel latch, the tool is configured as a lever with the fulcrum between the release handle engaging rod and the opposite handle end of the lever arm. The fulcrum is placed against the side of the trailer and force is applied to the handle end of the lever arm toward the trailer, thereby pulling the opposite end with its release handle rod, outwardly. The Joyce tool also requires significant upper body exertion, with the only difference between this tool and other lever type tools being that the applied force is directed toward the trailer, rather than away from the trailer.
U.S. Pat. No. 5,423,567 issued on Jun. 13, 1995 to Bobby R. Upton, titled “Tractor Trailer Fifth Wheel Lever/Cable Assembly,” describes a lever type tool comprising a bar having a fulcrum at one end and handle at the opposite end. A release handle pull cable extends from the general center area of the bar. The fulcrum is placed against the side of the trailer and an outward force is applied to the handle end of the bar, to apply a release force to the fifth wheel latch release handle. The Upton tool thus more closely resembles the tool of the Skaggs '089 U.S. Patent, discussed further above, than it does the present invention with its provision for the utilization of downward force provided by the body weight of the user for releasing the fifth wheel latch.
U.S. Pat. No. 5,626,063 issued on May 6, 1997 to Delbert D. Kosbab, titled “Tool For Unlocking A Fifth Wheel Locking Handle,” describes a device comprising an elongate bar with a T-shaped handle at one end and an offset catch at the opposite end. The catch is configured to capture the release handle of a fifth wheel hitch, and rotate the handle from its locked position to allow it to be pulled to release the hitch. The tool may also be used to apply the tensile force on the handle to release the hitch latch, but no leverage or amplification of force is provided by the Kosbab tool; all force must come from the upper body and back of the person using the tool. The present tool, with its change of direction of the required release force from the horizontal to the vertical, allows the body weight of the user to be used, thus avoiding the need for upper back exertion.
U.S. Pat. No. 5,863,060 issued on Jan. 26, 1999 to William E. Hollis et al., titled “Fifth Wheel King Pin Release Mechanism,” describes a permanently installed device which is a part of the hitch and release assembly of the truck. The device comprises a lever arm which is permanently installed to a fulcrum pivot at the fifth wheel plate, with a distal handle at the opposite end. The fifth wheel release handle is linked to the lever arm at an intermediate point thereon. Applying an outward force on the lever arm applies an amplified force to the release handle by means of the leverage provided. However, due to the generally outward and horizontal force applied, the Hollis et al. mechanism is more closely related to the portable devices of the Skaggs '089, Joyce '007, and Upton 567 U.S. Patents, discussed further above, than it is to the present invention with its downwardly applied force by means of the body weight of the user.
U.S. Pat. No. 5,882,027 issued on Mar. 16, 1999 to Steven A. Tevis, titled “Fifth Wheel Trailer Hitching Tool And Apparatus,” describes a tool for use with fifth wheel mechanisms for lighter semi-trailers generally towed by heavier pickup trucks having ball type hitches installed in their beds. The basic principle of the hitch release tool remains essentially the same as that described further above for tools used with truck tractor and semi-trailer fifth wheel hitches, however. Several embodiments are described by Tevis, but none facilitate the release of the hitch by the application of body weight to produce a downwardly oriented force to release the latch of the hitch mechanism.
U.S. Pat. No. 6,201,252 issued on Mar. 13, 2001 to William E. Hollis et al., titled “Fifth Wheel King Pin Release Mechanism,” appears to be related to the '060 U.S. Patent to the same inventors, discussed further above. The primary difference appears to be provision for holding the release handle in a fully opened, release position. However, the release handle mechanism of the '252 U.S. Patent is essentially the same as that of the '060 U.S. Patent to the same inventors, discussed further above, and the points of difference noted in the discussion of that device and the present invention are seen to apply here as well.
U.S. Pat. No. 6,354,642 issued on Mar. 12, 2002 to Scotty E. Haggerty, titled “Puller And Locator For Trailer Tandem Axle Units,” describes a multipurpose tool also useful in pulling the release handle of a fifth wheel hitch mechanism. The device comprises a telescoping rod and tension spring, with the spring applying force to release the slider locking pins of the tandem axle assembly of a semi-trailer. A hook is provided at the distal end of the assembly, for engaging the release handle of a fifth wheel hitch. The Haggerty tool is quite versatile, but its function as a fifth wheel release tool is limited due to the other functions of the device. Force for releasing the fifth wheel latch must be applied horizontally and outwardly with a straight pull on the Haggerty tool, thus requiring exertion of the muscles of the upper body and back. The present tool, with its downwardly disposed treadle or stirrup, provides the release force merely by the user stepping into the stirrup and applying his or her body weight to accomplish the task.
U.S. Patent Publication No. 2003/127,826 published on Jul. 10, 2003 to Dale Clemence, titled “Method And Device For Releasing A Fifth Wheel Hitch,” describes a device comprising a fifth wheel release handle hook linked by a chain to a transverse handle. The device is used by positioning the hook so that it is offset from the direction of the handle, and providing some slack in the chain. The handle is then jerked outwardly to pull the assembly taut, with the momentum applying a sudden high force to the hitch release handle. The Clemence device is thus more closely related to the slide hammer type hitch release tool of the Boring et al. '559 U.S. Patent, discussed further above, than it is to the present invention with its downwardly directed release force.
Finally, British Patent Publication No. 2,160,163 published on Dec. 18, 1985 to York Technical Services Ltd., titled “Fifth-Wheel Trailer Coupling,” describes a relatively complex fifth wheel latch and release mechanism which is installed as a permanent subassembly of the fifth wheel mechanism of a truck tractor. Various means for temporarily holding the mechanism, and release handle, in either the released or latched position are disclosed. However, no additional tools to facilitate the application of the required force to the release handle are disclosed by Bloomfield.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a fifth wheel release tool solving the aforementioned problems is desired.